Catalyst obstacles for pulse detonation device employed in a detonation device cleaning system

ABSTRACT

A pulse detonation device includes a body member having an outer wall and an inner wall that defines a pulse detonation zone and a plurality of obstacles extend along the pulse detonation zone. At least a portion of the plurality of obstacles include a combustion catalyst.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to coal burning systems and,more particularly, to catalyst obstacles provided in a pulse detonationdevice employed in a detonation cleaning system.

Industrial boilers operate by using a heat source to create steam fromwater or another working fluid, which can then be used to drive aturbine in order to supply power. Conventionally, the heat source is acombustor that burns a fuel in order to generate heat, which is thentransferred into the working fluid via a heat exchanger, such as a fluidconducting tube or pipe. Burning fuel may generate residues that oftenare left behind forming a buildup on surfaces of associated ducting orthe heat exchanger. This buildup can lead to performance degradationrelated to an increase in pressure drop, reduced fuel efficiency, anddamage to mechanical components. Performance degradation can eventuallylead to costly planned or unplanned outages. Periodic removal orprevention of such buildup maintains the operational efficiency of suchboiler systems. In the past, the buildup was removed by directingpressurized steam, water jets, acoustic waves, and mechanical hammeringonto the inner surfaces of the combustor or heat exchanger. However,such methods are often times costly and not always effective. Morerecently, detonative combustion devices are being used to remove thebuildup. Detonative combustion devices that burn customer friendlyfuels, such as natural gas and propane, tend to require large detonationchamber diameters and lengths, which, in turn, require a relativelylarge installation footprint. Moreover, in some cases, such detonationdevices require oxygen enrichment in order to create the detonations.Flexible fuels, or fuels having a large detonation cell size and highdirect initiation energy, such as natural gas and propane, do not burnproperly in existing systems without the addition of some amount ofoxygen. More specifically, when using flexible fuels in existingdetonative combustions devices, flame propagation velocity is less thandesired, resulting in little or no cleaning ability for the resultingcombustion process.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the invention, a pulse detonation deviceincludes a body member having an outer wall and an inner wall thatdefines a pulse detonation zone and a plurality of obstacles extendalong the pulse detonation zones. At least a portion of the plurality ofobstacles include a combustion catalyst.

According to another aspect of the invention, a detonation cleaningsystem includes a vessel having an interior chamber, and a pulsedetonation device operatively coupled to the vessel and fluidly coupledto the interior chamber. The pulse detonation device includes a bodymember having an outer wall and an inner wall that defines a pulsedetonation zone. A plurality of obstacles extend along at the pulsedetonation zone. At least a portion of the plurality of obstaclesincludes a combustion catalyst.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWING

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a top schematic view of an interior chamber of a vessel, shownin the form of an industrial boiler, having a pulse detonation deviceconstructed in accordance with an exemplary embodiment; and

FIG. 2 is a schematic cross-sectional view of the pulse detonationdevice of FIG. 2.

The detailed description explains embodiments of the invention, togetherwith advantages and features, by way of example with reference to thedrawings.

DETAILED DESCRIPTION OF THE INVENTION

With initial reference to FIG. 1, a detonation cleaning system 1 inaccordance with an exemplary embodiment includes a vessel, shown in theform of an industrial boiler is indicated generally at 2. Vessel 2includes a main body 4 having an outer surface 6 and an inner surface 7that defines an interior chamber 8. In the embodiment shown, vessel 2includes a flange 10 that is provided on main body 4. Cleaning system 1also includes a pulse detonation device 20 operatively connected toflange 10 and, as will become more fully evident below, an air source 23and a fuel source 24 that are electrically connected to a controller 40.Pulse detonation device 20 is selectively operated to direct asupersonic pulse detonation or shockwave 44 into interior chamber 8 todislodge or loosen any build-up of debris.

Pulse detonation device 20 includes a body member 83 having a first endor inlet 86 that extends to a second end or outlet 87 through anintermediate portion 89. With this arrangement, controller 40establishes a desired fuel/air mixture that is passed to inlet 86 ofpulse detonation device 20. The fuel air mixture is ignited to form apulse detonation wave that is directed through transition piece 91 andinto interior chamber 8 to loosen debris, such as soot that my beclinging to internal surfaces of vessels 2. Controller 40 is alsoconfigured to set a desired frequency of supersonic pulse detonationwave 44 emanating from pulse detonation device 20. Controller 40 can seta frequency of up to about 20 Hz for the pulse detonation wave. Thefrequency of the pulse detonation wave can be controlled to aid inestablishing non-uniform, frequency shifted, waves that cooperate todislodge the debris. Supersonic pulse detonation wave 44 can reachtemperatures up to about 2500° F. (1371.1° C.) degrees or better. Thehigh temperatures and non-uniform shockwaves achievable by the use of apulse detonation device cooperates to enhance the removal of debris fromvessel 2.

In accordance with an exemplary embodiment illustrated in FIG. 2, pulsedetonation device 20 includes a central pulse detonation tube 126arranged within body member 83, and an intermediate pulse detonationtube 128 arranged within body member 83 and about central pulsedetonation tube 126. Central pulse detonation tube 126 includes a firstend 132 that extends to a second end 133 through an intermediate portion134 that defines a first pulse detonation zone 135. In the embodimentshown, first end 132 defines a fuel and air inlet 137 coupled to fuelair source 23 and fuel source 24. Intermediate pulse detonation tube 128includes a first end 146 that extends to a second end 147 through anintermediate portion 148 that defines a second pulse detonation zone149. Second end 147 of intermediate pulse detonation tube 128 includes aflow redirection zone 152 having a curvilinear surface 154. As will bediscussed more fully below, flow redirection zone 152 guides a turbulentcombustion wave from first pulse detonation zone 135 toward second pulsedetonation zone 149.

Body member 83 of pulse detonation device 20 includes an outer wall 157and an inner wall 158 that defines a third pulse detonation zone 160. Inaddition, inlet 86 is shown to include a second flow redirection zone163 having a curvilinear surface 165. Second flow redirection zone 163redirects the turbulent combustion wave from second pulse detonationzone 149 toward third pulse detonation zone 160. With this arrangement,pulse detonation device 20 includes a curvilinear flow path thatpromotes the turbulent combustion wave into a shockwave that isdetonated to form supersonic pulse detonation wave 44. The curvilinearflow path enables pulse detonation device 20 to have a short overalllength while ensuring a desired detonation of the shockwave.

In order to further promote the shock wave and enhance detonation, afirst plurality of obstacles 171 extend along first pulse detonationzone 135. First plurality of obstacles 171 take the form of annulardiscs and are configured to bend/fold the turbulent combustion wave tohelp promote the shock wave. In accordance with one aspect of theexemplary embodiment, one or more of the first plurality of obstacles171 are formed from a combustion catalyst 173 that is configured toaid/promote the detonation of the shockwave. In accordance with anotheraspect of the exemplary embodiment, one or more of the first pluralityof obstacles 171 are coated with combustion catalyst 173. In eithercase, combustion catalyst 173 includes at least one of a chromium oxide,a cobalt oxide, an iron compound, a copper compound, palladium,platinum, and calcium nitrate. Of course it should be understood thatcombustion catalyst 173 can be formed from a variety of materials thatare configured to catalytically increase combustion.

In further accordance with the exemplary embodiment, a second pluralityof obstacles 178 extend along second pulse detonation zone 149. In amanner similar to that described above, second plurality of obstacles178 take the form of annular discs. In accordance with one aspect of theexemplary embodiment, one or more of the second plurality of obstacles178 are formed from a combustion catalyst 180 that is configured toaid/promote the detonation of the shockwave. In accordance with anotheraspect of the exemplary embodiment, one or more of the second pluralityof obstacles 178 are coated with combustion catalyst 180. In a mannersimilar to that described above, combustion catalyst 180 includes atleast one of a chromium oxide, a cobalt oxide, an iron compound, acopper compound, palladium, platinum, and calcium nitrate. As noteabove, combustion catalyst 180 can be formed from a variety of materialsthat are configured to catalytically increase combustion.

In still further accordance with the exemplary embodiment a thirdplurality of obstacles 184 extend along third pulse detonation zone 160.In a manner also similar to that described above, third plurality ofobstacles 184 take the form of annular discs. In accordance with oneaspect of the exemplary embodiment, one or more of the third pluralityof obstacles 184 are formed from a combustion catalyst 186 that isconfigured to aid/promote the detonation of the shockwave. In accordancewith another aspect of the exemplary embodiment, one or more of thethird plurality of obstacles 184 are coated with catalyst 186. In amanner similar to that described above, catalyst 186 includes at leastone of a chromium oxide, a cobalt oxide, an iron compound, a coppercompound, palladium, platinum, and calcium nitrate. Also, as note above,combustion catalyst 180 can be formed from a variety of materials thatare configured to catalytically increase combustion.

Combustion catalysts 173, 180 and 186 react with the shockwave topromote detonation. The addition of combustion catalysts 173, 180, and186 to obstacles 171, 178 and 184 respectively allows pulse detonationdevice 20 to have a much shorter length than currently achievable byexisting pulse detonation devices. At this point it should be understoodthat while described as annular discs, the obstacles can take on avariety of forms. Also, in addition to forming/coating the obstacleswith the combustion catalyst, pulse detonation device 20 could also beconstructed with one or more of the central pulse detonation tube, theintermediate pulse detonation tube, and the inner wall of the bodymember being formed from, or coated with, a combustion catalyst.Finally, the particular type, and/or geometry of the pulse detonationdevice could vary. That is, while shown as a reverse flow pulsedetonation device, e.g., a detonation device that includes a curvilineardetonation path, the obstacles could also be employed in detonationdevices having a substantially linear detonation path.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

1. A pulse detonation device comprising: a body member having an outerwall and an inner wall that defines a pulse detonation zone; and aplurality of obstacles extending along the pulse detonation zone, atleast a portion of the plurality of obstacles including a combustioncatalyst.
 2. The pulse detonation device according to claim 1, furthercomprising: at least one pulse detonation tube arranged within the bodymember, the at least one pulse detonation tube including a first endthat extends to a second end through an intermediate portion thatdefines another pulse detonation zone
 3. The pulse detonation zoneaccording to claim 2, wherein the plurality of obstacles include a firstplurality of obstacles that extend along the pulse detonation zone andanother plurality of obstacles that extend along the another pulsedetonation zone.
 4. The pulse detonation device according to claim 2,wherein the at least one pulse detonation tube includes a central pulsedetonation tube having a first end that extends to a second end throughan intermediate portion that defines the another pulse detonation zone,and an intermediate pulse detonation tube having a first end thatextends to a second end through an intermediate portion that definesstill another pulse detonation zone.
 5. The pulse detonation deviceaccording to claim 4, wherein the plurality of obstacles include a firstplurality of obstacles that extend along the pulse detonation zone, asecond plurality of obstacles that extend along the another pulsedetonation zone, and a third plurality of obstacles that extend alongthe still another pulse detonation zone.
 6. The pulse detonation deviceaccording to claim 4, wherein the second end of the intermediate pulsedetonation tube includes a first flow redirection zone, the second endof the central pulse detonation tube being arranged that the first flowredirection zone.
 7. The pulse detonation device according to claim 6,further comprising: a second flow redirection zone arranged downstreamfrom the first end of the intermediate pulse detonation tube.
 8. Thepulse detonation device according to claim 1, wherein the portion of theplurality of obstacles are formed from the combustion catalyst.
 9. Thepulse detonation device according to claim 1, wherein the portion of theplurality of obstacles are coated with the combustion catalyst.
 10. Thepulse detonation device according to claim 1, wherein all of theplurality of obstacles include the combustion catalyst.
 11. The pulsedetonation device according to claim 1, wherein the combustion catalystincludes at least one of a chromium oxide, a cobalt oxide, an ironcompound, a copper compound, palladium, platinum, and calcium nitrate.12. A detonation cleaning system comprising: a vessel having an interiorchamber; and a pulse detonation device operatively coupled to the vesseland fluidly coupled to the interior chamber, the pulse detonation devicecomprising: a body member having an outer wall and an inner wall thatdefines a first pulse detonation zone; and a plurality of obstaclesextending along the pulse detonation zone, at least a portion of theplurality of obstacles including a combustion catalyst.
 13. Thedetonation cleaning system according to claim 12, wherein the portion ofthe plurality of obstacles are formed from the combustion catalyst. 14.The detonation cleaning system according to claim 12, wherein theportion of the plurality of obstacles are coated with the combustioncatalyst.
 15. The detonation cleaning system according to claim 12,wherein all of the plurality of obstacles include the combustioncatalyst.
 16. The detonation cleaning system according to claim 12,further comprising: at least one pulse detonation tube arranged withinthe body member, the at least one pulse detonation tube including afirst end that extends to a second end through an intermediate portionthat defines another pulse detonation zone
 17. The pulse detonationdevice according to claim 16, wherein the at least one pulse detonationtube includes a central pulse detonation tube having a first end thatextends to a second end through an intermediate portion that defines theanother pulse detonation zone, and an intermediate pulse detonation tubehaving a first end that extends to a second end through an intermediateportion that defines a still another pulse detonation zone.
 18. Thepulse detonation device according to claim 17, wherein the plurality ofobstacles include a first plurality of obstacles that extend along thepulse detonation zone, a second plurality of obstacles that extend alongthe another pulse detonation zone, and a third plurality of obstaclesthat extend along the still another pulse detonation zone.
 19. The pulsedetonation device according to claim 17, wherein the second end of theintermediate pulse detonation tube includes a first flow redirectionzone, the second end of the central pulse detonation tube being arrangedthat the first flow redirection zone.
 20. The pulse detonation deviceaccording to claim 19, further comprising: a second flow redirectionzone arranged downstream from the first end of the intermediate pulsedetonation tube.